This update for grub2 fixes the following issues :

Fix for CVE-2020-10713 (bsc#1168994)

Fix for CVE-2020-14308 CVE-2020-14309, CVE-2020-14310, CVE-2020-14311 (bsc#1173812)

Fix for CVE-2020-15706 (bsc#1174463)

Fix for CVE-2020-15707 (bsc#1174570)

Use overflow checking primitives where the arithmetic expression for buffer allocations may include unvalidated data

Use gcc-9 compiler for overflow check builtins

Backport gcc-9 build fixes

Fix packed-not-aligned error on GCC 8 (bsc#1084632)

Backport gcc-7 build fixes

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:3227 advisory.

    The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and     customizable boot loader with modular architecture. The packages support a variety of kernel formats, file     systems, computer architectures, and hardware devices.

    The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot     loader under secure boot environments.

    The fwupd packages provide a service that allows session software to update device firmware.

    Security Fix(es):

    * grub2: Crafted grub.cfg file can lead to arbitrary code execution during boot process (CVE-2020-10713)

    * grub2: grub_malloc does not validate allocation size allowing for arithmetic overflow and subsequent     heap-based buffer overflow (CVE-2020-14308)

    * grub2: Integer overflow in grub_squash_read_symlink may lead to heap-based buffer overflow     (CVE-2020-14309)

    * grub2: Integer overflow read_section_as_string may lead to heap-based buffer overflow (CVE-2020-14310)

    * grub2: Integer overflow in grub_ext2_read_link leads to heap-based buffer overflow (CVE-2020-14311)

    * grub2: Fail kernel validation without shim protocol (CVE-2020-15705)

    * grub2: Use-after-free redefining a function whilst the same function is already executing     (CVE-2020-15706)

    * grub2: Integer overflow in initrd size handling (CVE-2020-15707)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:3271 advisory.

    The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and     customizable boot loader with modular architecture. The packages support a variety of kernel formats, file     systems, computer architectures, and hardware devices.

    The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot     loader under secure boot environments.

    The fwupdate packages provide a service that allows session software to update device firmware.

    Security Fix(es):

    * grub2: Crafted grub.cfg file can lead to arbitrary code execution during boot process (CVE-2020-10713)

    * grub2: grub_malloc does not validate allocation size allowing for arithmetic overflow and subsequent     heap-based buffer overflow (CVE-2020-14308)

    * grub2: Integer overflow in grub_squash_read_symlink may lead to heap-based buffer overflow     (CVE-2020-14309)

    * grub2: Integer overflow read_section_as_string may lead to heap-based buffer overflow (CVE-2020-14310)

    * grub2: Integer overflow in grub_ext2_read_link leads to heap-based buffer overflow (CVE-2020-14311)

    * grub2: Fail kernel validation without shim protocol (CVE-2020-15705)

    * grub2: Use-after-free redefining a function whilst the same function is already executing     (CVE-2020-15706)

    * grub2: Integer overflow in initrd size handling (CVE-2020-15707)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

    Bug Fix(es):

    * grub2 should get resynced with 7.8 branch (BZ#1861857)

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to the versions of the grub2 packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities :

  - A flaw was found in grub2, prior to version 2.06. An     attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows     the bypass of Secure Boot protections. In order to load     an untrusted or modified kernel, an attacker would     first need to establish access to the system such as     gaining physical access, obtain the ability to alter a     pxe-boot network, or have remote access to a networked     system with root access. With this access, an attacker     could then craft a string to cause a buffer overflow by     injecting a malicious payload that leads to arbitrary     code execution within GRUB. The highest threat from     this vulnerability is to data confidentiality and     integrity as well as system     availability.(CVE-2020-10713)

  - Integer overflows were discovered in the functions     grub_cmd_initrd and grub_initrd_init in the efilinux     component of GRUB2, as shipped in Debian, Red Hat, and     Ubuntu (the functionality is not included in GRUB2     upstream), leading to a heap-based buffer overflow.
    These could be triggered by an extremely large number     of arguments to the initrd command on 32-bit     architectures, or a crafted filesystem with very large     files on any architecture. An attacker could use this     to execute arbitrary code and bypass UEFI Secure Boot     restrictions. This issue affects GRUB2 version 2.04 and     prior versions.(CVE-2020-15707)

  - GRUB2 contains a race condition in     grub_script_function_create() leading to a     use-after-free vulnerability which can be triggered by     redefining a function whilst the same function is     already executing, leading to arbitrary code execution     and secure boot restriction bypass. This issue affects     GRUB2 version 2.04 and prior versions.(CVE-2020-15706)

  - There is an issue with grub2 before version 2.06 while     handling symlink on ext filesystems. A filesystem     containing a symbolic link with an inode size of     UINT32_MAX causes an arithmetic overflow leading to a     zero-sized memory allocation with subsequent heap-based     buffer overflow.(CVE-2020-14311)

  - There is an issue on grub2 before version 2.06 at     function read_section_as_string(). It expects a font     name to be at max UINT32_MAX - 1 length in bytes but it     doesn't verify it before proceed with buffer allocation     to read the value from the font value. An attacker may     leverage that by crafting a malicious font file which     has a name with UINT32_MAX, leading to     read_section_as_string() to an arithmetic overflow,     zero-sized allocation and further heap-based buffer     overflow.(CVE-2020-14310)

  - There's an issue with grub2 in all versions before 2.06     when handling squashfs filesystems containing a     symbolic link with name length of UINT32 bytes in size.
    The name size leads to an arithmetic overflow leading     to a zero-size allocation further causing a heap-based     buffer overflow with attacker controlled     data.(CVE-2020-14309)

  - In grub2 versions before 2.06 the grub memory allocator     doesn't check for possible arithmetic overflows on the     requested allocation size. This leads the function to     return invalid memory allocations which can be further     used to cause possible integrity, confidentiality and     availability impacts during the boot     process.(CVE-2020-14308)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote SUSE Linux SLES11 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2020:14440-1 advisory.

  - A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability. (CVE-2020-10713)

  - In grub2 versions before 2.06 the grub memory allocator doesn't check for possible arithmetic overflows on     the requested allocation size. This leads the function to return invalid memory allocations which can be     further used to cause possible integrity, confidentiality and availability impacts during the boot     process. (CVE-2020-14308)

  - There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a     symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow     leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled     data. (CVE-2020-14309)

  - There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font     name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer     allocation to read the value from the font value. An attacker may leverage that by crafting a malicious     font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow,     zero-sized allocation and further heap-based buffer overflow. (CVE-2020-14310)

  - There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem     containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a     zero-sized memory allocation with subsequent heap-based buffer overflow. (CVE-2020-14311)

  - GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability     which can be triggered by redefining a function whilst the same function is already executing, leading to     arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and     prior versions. (CVE-2020-15706)

  - Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux     component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2     upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number     of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files     on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot     restrictions. This issue affects GRUB2 version 2.04 and prior versions. (CVE-2020-15707)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2021:0048 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2020-10713:
    A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability.

    CVE-2020-10759:
    A PGP signature bypass flaw was found in fwupd (all versions), which could lead to the installation of     unsigned firmware. As per upstream, a signature bypass is theoretically possible, but not practical     because the Linux Vendor Firmware Service (LVFS) is either not implemented or enabled in versions of fwupd     shipped with Red Hat Enterprise Linux 7 and 8. The highest threat from this vulnerability is to     confidentiality and integrity.

    CVE-2020-14372:
    A flaw was found in grub2 in versions prior to 2.06, where it incorrectly enables the usage of the ACPI     command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a     Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable     content directly into memory. The table is further loaded and executed by the kernel, defeating its Secure     Boot lockdown and allowing the attacker to load unsigned code. The highest threat from this vulnerability     is to data confidentiality and integrity, as well as system availability.

    CVE-2020-25632:
    A flaw was found in grub2 in versions prior to 2.06. The rmmod implementation allows the unloading of a     module used as a dependency without checking if any other dependent module is still loaded leading to a     use-after-free scenario. This could allow arbitrary code to be executed or a bypass of Secure Boot     protections. The highest threat from this vulnerability is to data confidentiality and integrity as well     as system availability.

    CVE-2020-25647:
    A flaw was found in grub2 in versions prior to 2.06. During USB device initialization, descriptors are     read with very little bounds checking and assumes the USB device is providing sane values. If properly     exploited, an attacker could trigger memory corruption leading to arbitrary code execution allowing a     bypass of the Secure Boot mechanism. The highest threat from this vulnerability is to data confidentiality     and integrity as well as system availability.

    CVE-2020-27749:
    A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied     command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage,     without sufficient bounds checking. If the function is called with a command line that references a     variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack     frame and control execution which could also circumvent Secure Boot protections. The highest threat from     this vulnerability is to data confidentiality and integrity as well as system availability.

    CVE-2020-27779:
    A flaw was found in grub2 in versions prior to 2.06. The cutmem command does not honor secure boot locking     allowing an privileged attacker to remove address ranges from memory creating an opportunity to circumvent     SecureBoot protections after proper triage about grub's memory layout. The highest threat from this     vulnerability is to data confidentiality and integrity as well as system availability.

    CVE-2021-20225:
    A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past     the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms     of options. The highest threat from this vulnerability is to data confidentiality and integrity as well as     system availability.

    CVE-2021-20233:
    A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs     a length calculation on the assumption that expressing a quoted single quote will require 3 characters,     while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each     quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as     well as system availability.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Published	Updated	Severity
139175	SUSE SLES12 Security Update : grub2 (SUSE-SU-2020:2076-1)	Nessus	SuSE Local Security Checks	7/30/2020	2/27/2024	high
139192	RHEL 8 : grub2 (RHSA-2020:3227)	Nessus	Red Hat Local Security Checks	7/30/2020	11/7/2024	high
139288	RHEL 7 : grub2 (RHSA-2020:3271)	Nessus	Red Hat Local Security Checks	8/3/2020	11/7/2024	high
147445	EulerOS Virtualization 2.9.1 : grub2 (EulerOS-SA-2021-1601)	Nessus	Huawei Local Security Checks	3/10/2021	1/11/2024	high
150632	SUSE SLES11 Security Update : grub2 (SUSE-SU-2020:14440-1)	Nessus	SuSE Local Security Checks	6/10/2021	12/26/2023	high
236732	Alibaba Cloud Linux 3 : 0048: fwupd (ALINUX3-SA-2021:0048)	Nessus	Alibaba Cloud Linux Local Security Checks	5/14/2025	5/15/2025	high

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